package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.function.Function;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {
    @Resource
    private IUserService userService;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private IFollowService followService;

    @Override
    public Result saveBlog(Blog blog) {
        // 获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        // 保存探店博文
        boolean isSave = save(blog);
        //判断是否保存成功
        if(!isSave){
            return Result.fail("新增笔记失败");
        }
        // 查询笔记作者的所有粉丝 select * from tb_follow where follow_user_id = ?
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
        // 推送笔记id给所有粉丝
        for (Follow follow : follows) {
            // 4.1.获取粉丝id
            Long userId = follow.getUserId();
            // 4.2.推送
            String key = FEED_KEY + userId;
            stringRedisTemplate.opsForZSet().add(key, blog.getId().toString(), System.currentTimeMillis());
        }
        // 返回id
        return Result.ok(blog.getId());
    }

    //分页查询
    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog ->{
            //手动维护，添加use信息，以及是否点过赞
            this.queryBlogUser(blog);
            this.isBlogLiked(blog);
        });
        return Result.ok(records);
    }

    @Override
    public Result queryBlogById(Long id) {
        //查询blog
        Blog blog = getById(id);
        if(blog == null){
            return Result.fail("笔记不存在");
        }
        //查询blog有关的用户
        queryBlogUser(blog);
        //查询blog是否被点赞
        isBlogLiked(blog);
        return Result.ok(blog);
    }

    //把是否点过赞存到blog
    private void isBlogLiked(Blog blog) {
        //获取登录用户
        UserDTO user = UserHolder.getUser();
        if(user==null){
            //用户未登录，无需查询是否点赞
            return ;
        }
        Long userId = UserHolder.getUser().getId();
        String key = RedisConstants.BLOG_LIKED_KEY+blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike( score!=null );
    }

    //把用户信息存到blog中
    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }

    @Override
    public Result likeBlog(Long id) {
        //获取登录用户
        Long userId = UserHolder.getUser().getId();
        String key = RedisConstants.BLOG_LIKED_KEY+id;
        //判断用户是否点过赞
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        if(score == null){
            //没有则可以进行点赞
            //数据库点赞加1
            boolean idUpdate = update().setSql("liked = liked + 1").eq("id", id).update();
            //存储到SortedSet集合，因为要对点赞时间进行排序，因此set不符合，改为SortSet
            if(BooleanUtil.isTrue(idUpdate)){
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
            }
        }else{
            //已经点过赞再点击就取消点赞
            boolean idUpdate = update().setSql("liked = liked - 1").eq("id", id).update();
            //存储到set集合
            if(BooleanUtil.isTrue(idUpdate)){
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
            }
        }
        return Result.ok();
    }

    @Override
    public Result queryBlogLikes(Long id) {
        String key = RedisConstants.BLOG_LIKED_KEY + id;
        //查询top5点赞用户
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        //可能为空并没有出错，但不能返回null回去，应该返回空集合回去
        if(top5 == null || top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        //解析出其中的用户id
        List<Long> userIdList = top5.stream().map(new Function<String, Long>() {
            @Override
            public Long apply(String s) {
                return Long.valueOf(s);
            }
        }).collect(Collectors.toList());
        //根据用户id查询用户
        List<UserDTO> userDTOList = userService.listByIds(userIdList)
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());

//        String idStr = StrUtil.join(",", userIdList);
//        userService
//                //对比上面的，下面的是mybatisPlus的自己写语句用last()
//                .query()
//                .in("id",userIdList).last("ORDER BY FIELD(id,"+idStr+")").list()
//                .stream()
//                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
//                .collect(Collectors.toList());
        //返回
        return Result.ok(userDTOList);
    }

    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //获取当前用户
        Long userId = UserHolder.getUser().getId();
        //查询收件箱，获取信件
        String key = FEED_KEY + userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 3);
        //非空判断
        if(typedTuples ==null ||typedTuples.isEmpty()){
            return Result.ok();
        }
        //解析数据：blogId、min时间戳、offset(上次查询时一样的最小值)
        long minTime = 0;
        int offs = 0;
        //提前设置好空间，无需后面扩容浪费性能
        List<Long> blogList = new ArrayList<>(typedTuples.size());
        for(ZSetOperations.TypedTuple<String> typedTuple:typedTuples){
            //获取blogId
            blogList.add(Long.valueOf( typedTuple.getValue()));
            //获取分数，时间戳
            long time = typedTuple.getScore().longValue();
            if(time == minTime){
                offs++;
            }else{
                minTime = time;
                offs = 1;
            }
        }
        // 5.根据id查询blog
        String idStr = StrUtil.join(",", blogList);
        List<Blog> blogs = query().in("id", blogList).last("ORDER BY FIELD(id," + idStr + ")").list();

        for (Blog blog : blogs) {
            // 5.1.查询blog有关的用户
            queryBlogUser(blog);
            // 5.2.查询blog是否被点赞
            isBlogLiked(blog);
        }

        // 6.封装并返回
        ScrollResult r = new ScrollResult();
        //返回信件
        r.setList(blogs);
        //下次查询的信息
        r.setOffset(offs);
        r.setMinTime(minTime);

        return Result.ok(r);
    }
}
